Work feeding mechanisms for sewing machines



April 1960 R. E. JOHNSON WORK FEEDING MECHANISMS FOR SEWING MACHINESFiled April 12, 1957 5 SheetsSheet l Ralph E. Johnson tilltiy 1 13-hTTORNEY April 5, 1960 R. E. JOHNSON WORK FEEDING MECHANISMS FOR SEWINGMACHINES 5 Sheets-Sheet 2 Filed April 12, 1957 IN V EN TOR.

Ralph E. Johnson NQTORNEY April 5, 1960 R. E. JOHNSON WORK FEEDINGMECHANISMS FOR sswmc MACHINES 5 Sheets-Sheet 3 Filed April 12, 1957INVENTOR. Ralph E. Johnson TORNEY Aprii 5, 1960 R. E. JOHNSON WORKFEEDING MECHANISMS FOR SEWING MACHINES Filed April 12, 1957 5Sheets-Sheet 4 INVENTOR Ralph E. Johnson Aprifl 5, 196% R. E. JOHNSONWORK FEEDING MECHANISMS FOR SEWING MACHINES Filed April 12, 1957 5Sheets-Sheet 5 xlrlluki IN V EN TOR. Ralph E. Johnson United StatesPatentO WORK FEEDING IHECHANISMS FOR SEWING MACHINES Application April12, 1957, Serial No. 652,412

11 Claims. (Cl. 112-210) This invention relates to work feedingmechanisms for sewing machines, and more particularly, to a drop feed orfour motion type of work feeding mechanism operable to advance the workfabric across the bed of a cylinder bed type of sewing machine.

It is an object of this invention to provide a new and improved fourmotion drop feed mechanism providing a work feeding motion having a fiatfeed advancing motion across the bed of a cylinder bed of a sewingmachine.

In order that the fabric can be stitched into tubes of the smallestpossible diameter, it is advantageous in sewing machines having acylinder bed construction to maintain the smallest possible crosssection of the bed. From the point of view of the work feedingmechanism, however, an attenuated cylindrical bed of small cross sectionis conducive to many serious problems to the solution of which thepresent invention is directed.

The limited space available within a cylinder bed has presenteddifficulties in obtaining a feed motion of a desired accuracy andprecision. The cramped quarters and limited clearances within thecylinder bed have in the past given rise to arrangements in which thefeed motions are derived from necessarily small motions of feedactuating mechanisms. In these cases, the effects of normal play in theparts, lost motion, tolerances, etc., are magnified in the feed motionand precision of feed motion suifers.

In some prior art constructions the desirable fiat feed motion has beensacrificed in favor of an arcuate motion in order to surmount thedifficulties encountered in properly actuating a feed mechanism within acylinder bed.

It is an object of this invention to provide a novel work feedingmechanism for a sewing machine in which highly accurate and precise flatfeed motion above the throat plate is obtained.

It is another object of this invention to provide a work feedingmechanism of the above character which is supported and actuated in anovel fashion so as to be subject, during operation, to a minimum ofobjectionable deformation.

With the above and other objects and advantages in view as willhereinafter appear, this invention comprises the devices, combinationsand arrangements of parts hereinafter described and illustrated in theaccompanying drawings of a preferred embodiment in which:

Fig. 1 represents a side elevational view of a sewing machine withportions of the machine frame broken away and shown in vertical crosssection, illustrating the feed mechanism of my invention appliedthereto,

Fig. 2 is a vertical cross sectional view of the head end of the sewingmachine taken substantially along line 22 of Fig. 1,

Fig. 3 is a vertical cross sectional view of the standard end of thesewing machine taken substantially along line 33 of Fig. 1,

Fig. 4 represents a bottom plan view of the sewing machine of Fig. 1with the cylinder bed bottom cover removed,

2,931,329 Patented Apr. 5, 1960 ice Fig. 5 is a vertical cross sectionalview of the work supporting bed taken substantially along line 5--5 ofFig. 4,

Fig. 6 is a vertical cross sectional view of the machine base takensubstantially along line 6-6 of Fig. 4,

Fig. 7 represents a top plan view of the sewing machine base with thefeed mechanism shown in dotted lines,

Fig. 8 is a vertical cross sectional view taken substantially along line88 of Fig. 7,

Fig. 9 represents a bottom plan view of a modified form of sewingmachine base, illustrating the feed mechanism of my invention appliedthereto, and

Fig. 10 is an enlarged vertical cross sectional view taken substantiallyalong line 10-10 of Fig. 9.

Referring particularly to Figs. 1 to 4, this invention is illustrated asapplied to a sewing machine of the type having a frame base 10 formedwith free ended tubular work supporting bed 11 of the so-called cylinderbed variety. The bed 11 need not be a true cylinder but only anapproximation thereof around which tubular articles may be placed forsewing. At the bottom the bed is closed by a removable bottom cover 12to prevent interference of Work fabrics with the mechanism within thebed. Any known type of support (not shown) may be interposed between thebase 10 and a supporting table top or other surface to support thesewing machine with the work supporting bed in spaced relation above themachine supporting surface. Figs. 2, 4 and 7 best illustrate that thebed 11 is offset toward the front of the machine frame base, that is,the bed is arranged to extend from that side of the base nearest theoperator. That portion of the machine frame which is above the framebase 11 may be of the type illustrated and described in my copendingpatent application Serial No. 471,766, filed November 29, 1954, nowPatent No. 2,862,468, dated December 2, 1958, to which reference may behad for a more complete disclosure. For purposes of the presentinvention it is sufiicient to understand that the upper portion of themachine frame comprises a hollow vertical standard 13 which supports abracket arm 14 terminating in a downwardly and forwardly inclined head15. A main shaft 16, journaled for rotation in the bracket arm, drivesan endwise reciprocatory needle bar 17 which is inclined downwardly andforwardly in the head 15. A needle 18 clamped on the needle barreciprocates through a needle aperture 19 in a throat plate 20 securedon the work supporting bed 12 and cooperates in the formation of lockstitches with a rotary loop taker 21 carried in the bed. Reference maybe had to my copending US. patent application Serial No. 634,904, filedJanuary 18, 1954, for a complete description of the loop taker. Forpurposes of the present invention it will be sufiicient to understandthat the loop taker 21 is rotatable about a vertical axis disposed infront of or toward the position of the machine operator from thestitching point as defined by the needle aperture in the throat plate.The loop taker is fast on a loop taker shaft 22 journaled vertically onthe work supporting bed. A bevel gear 23 fast on the loop taker shaft 22meshes with a bevel gear 24 on a bed shaft 25 which extends into themachine base 11. Meshing bevel gears 26 and 27 operatively connect thebed shaft with a shaft 28 journaled vertically in the standard andmeshing bevel gears 29 and 30 operatively connect the vertical shaft 28with the main shaft 16 in the bracket arm of the machine frame.

The work feeding mechanism of the present invention, as applied to theabove described cylinder bed sewing machine, comprises a T shaped feedbar, indicated gen erally as 35, of which the cross bar portion 36 isdisposed within the confines of the frame base 11 and extendssubstantially transversely thereof. A stem portion '37 at the l' shapedreed "bar extends lengthwise within substantially the entirelength "ofthe work supporting cylinder bed 12. Preferably, the stem portion 37 ofthe feed bar extends along the rear wall of the cylinder bed and adiagonal brace 38 which extendsdiag'onally from the stem to one limb ofthe cross bar portion of the feedbar may be included to stabilize thefeed bar. Se "cured to the feed bar at the free extremity of the stemportion 37 at a point rearwardly of'the stitching point, that is on theopposite side of the stitching point from the axis of the loop takershaft 22, is a feed dog 39 made fast on the feed bar by screws 40. Thefeed dog is formed with a plurality of transversely serrated clothgripping surfaces 41 certain of which extend across the stitching pointand all operating through slots 42 in the throat plate to grip andadvancethe 'WOIk. V

Extending from the stem portion of the feed bar at points thereon spacedapart lengthwise of the work supporting arm are a pair of arms 43, Fig.8, each extending downwardly and outwardly toward the front 'of the"machine. Pivotally secured to the free extremity'ofeach of the arms 43is a short link 44 which extends substantially vertically upwardly fromthe arms 43. The "upper extremity of each link 44 is pivotally securedto the free extremity of one of a pair of rock arms '45 which extendupwardly and outwardly toward the front 'of the machine from a feed liftrock shaft 46 and terminate substantially verticallyabove said feed bara'rm 43.

The feed lift rock shaft is disposed substantially verti cally beneaththe stem portion of the feed bar a'nd is 'journaled in a pintle 47 fastbeneath theframe base and a pintle 48 fast in the free extremityofthework supporting cylinder bed 12. Referring to Figsfila'nd be madeas an integral part of the driving gear 30 and 'a feed advance eccentric'or cam 52. With this construction the feed lift motion will. alwaysoccur'in predetermined timed relation with the feed advance motion andthe timing of both of thefeed motions with the rotary hook'may beaccomplished readily by an angular adjustment of any one of the gears inthe train of hook driving gears, as for instance by an angularadjustment,

of the gear 29 relatively to the shaft 28. V

The feed advance cam 52 is embraced by the bifurcated jaws -53 of a feedadvance pitman 54 which extends downwardly through the hollow standardand is pivotally connected to the free extremity of a rock arm; 55 faston a feed advance rock shaft 56 journaled between hearing pintles 57carried in the frame base 11. The feed advance rock shaft is formed withan upstanding rock arm 58 disposed substantially at a right angle to therock arm 55. At its upper free extremity, the rock arm 58 ispivotallysecured to the rearward limb of the cross bar portion 36 of theT shaped feed bar 35 W H Regulation of the length of work feeding strokeis attained by means of a slide block 59 pivoted on a 'stud 60 threadedinto the feed advance pitrnan in the machine standard. The slide block59 is embraced in a guide slot 61 formed in a feed regulating andreversing lever 62 fulcrumed on a stud 63 carried in the machinestandard. The feed regulating lever includes a threaded handle 64 whichextends through a slot 65 formed in the front wall of the standard andthrough a slot 66 with indicia plate 67 carried by the standard. Bymeans of a knurled adu'stingnut 68, any desired stitch length can bedetermined or the direction of stitching reversed by shifting enemas isbifurcated, as indicated at.70,' and embraces a stabiliiing guide roller71 journaled on a shouldered screw 'nism. The limbs of the feed bar maypreferably be ribbed, as illustrated particularly in the cross sectional'views Figs. 5, 6 and 8, to provide for rigid vertical der bed. The legportion thus provides a steadier supthe handle '64 to changethe'angular' relation between the guide slot 61 and the feed advancepitman 54. V

The forward limb of the, cross bar portion of the feed bar beyond itsjuncture with the diagonal cross brace 38 stability of the feed bar. TheT shape of'the feed bar 'alsoprovides for operable connections with thefeed actuating mechanism in a manner conducive to movement in a highlydesirable path which produces a linear feed straight across the cylinderwork supporting bed of the machine and an advantageously flatfeed'advancing motion ofthe feed dog. Considering the feed advanceactuating connection to the feed bar and referring to Figs. 4 and '6, itwill be noted that the construction thereof "provides for an extremelyWide spacing between the point of'conn'ection of thefeed advance rockarm '58 with 'the :feed bar am; th'e'islidable stabilizingconn'ectionbetween the bifurcated portion 70 of the feed bar and theguide roller 71. Also as illustrated'in Figs.

.feed bar, and the stabilizing connection of the feed'bar with the guideroller 71 occurs at the opposite side of the feed lift connections.Since these connections are spaced apart inthe relatively wide framebase 10,. rather than being crowded together inithe cylinder bed as isconventional in this type of machine, any tendency for the feed bar to rock idly i'n a horizontal plane is minimized. Considering the feed liftmotion-and referring particularly to Figs. 7 and 8, the pair ofconnections between the feed lift rock shaft and the feed bar beingspaced lengthwise of the stem portion 37 of the feed barresist any'tendency for the feed bar to rock idly in 'a verticalplan'e. The shortlinks 44 which depend from the feed lift rock arms 45 to the feed bararms 43 give rise to a lifting motion of the feed bar at the beginningand end of each feed advance stroke to augment the motion imparted by'thefe ed lifting mechanism and thereby to provide an extremely-fiatfeed advance motion which is considered desirable because the workfabrics will then be gripped evenly and continuously by the feed dogduring a greater portion of the feed advance stroke than with heretoforeconventional arrangements.

Thefpresent invention provides a compact work feedingfmechani'sm whichmay not only be confined within the limited space available in acylinder bed of 'a sewing machine but which is adapted to be arranged atone side of, and in the preferred form to the rear of, the vertical axisrotary loop taker within a cylinder bed. This feature is highlyadvantageous inasmuch as it makes possible a feed dog arrangement whichis cantilevered over the stitching point from only one side leaving theother side open for ready access to the loop taker as, for instance, forremoving and, replacing a bobbin therein.

Referring to Figs. '9 and 10, the feed mechanism of this inventionisillustrated as applied to ,a modified form of sewing machine frame whichdiffers from that previously described in that the frame base 10 isformed with an hutwardly projectingale'g portion 80. As indicated in thedrawings, the leg portion extends substantially parallcl to the cylinderbedll and rearwardly thereof with respect to the normal position of themachine operator. 7

A space 81 is provided between the leg 80 and the cylinder bed llforpassage of work fabrics. around'th'e cylinport for the sewing machineto minimize tipping of the machine. In the embodiment illustrated inFigs. 9 and 10, the woi k feeding mechanism remains unchanged except forthe feed advance rock shaft 56 which has been extended as at 56' withinthe leg portion 80 of the frame substantially the entire length thereof.A pintle 82 carried in the extremity of the leg portion is embraced bythe extended portion 56 of the feed advance rock shaft. This extendedfeed advance rock shaft provides not only for more convenient access tothe outboard pintle 82 thereof, but being elongate provides for anextremely stable feed advance actuating connection to the feed bar, thatis, one in which lost motion, etc. between the pintles 82 and 57 and thefeed bar will reflect in a minimum of objectionable rocking movementbeing transmitted to the feed bar.

Having thus set forth the nature of the invention, what I claim hereinis:

1. A four motion work feeding mechanism for a sewing machine having aframe base and a free ended Work supporting bed extending from saidframe base, comprising a feed bar formed with mutually perpendicularlimbs, a first of said limbs extending lengthwise within the worksupporting bed, a second of said limbs extending within said frame base,feed lift actuating mechanism including a feed lift rock shaft extendinglengthwise within the work supporting bed, a plurality of operativeconnections between said feed lift rock shaft and said feed bar, saidconnections arranged at points on the first of said limbs spacedlengthwise of said work supporting bed, and feed advance actuatingmechanism including a feed advance rock shaft disposed within said framebase, an operative connection between said feed advance rock shaft andsaid second limb of said feed bar, and means for actuating said feedadvance and said feed lift rock shafts.

2. A four motion work feeding mechanism for a sewing machine having aframe including a base and a free ended work supporting bed extendingfrom said frame base, comprising a feed bar formed with mutuallyperpendicular limbs, a first of said limbs extending lengthwise withinthe work supporting bed, a second of said limbs extending within saidframe base, feed lift actuating mechanism including a feed lift rockshaft extending lengthwise within the Work supporting bed, means foractuating said feed lift rock shaft, a plurality of operativeconnections between said feed lift rock shaft and said feed bar, saidconnections arranged at points on the first of said limbs spacedlengthwise of said work supporting bed, feed advance actuating mechanismincluding a feed advance rock shaft disposed within said frame base,means for actuating said feed advance rock shaft, an operativeconnection between said feed advance rock shaft and said second limb ofsaid feed bar, and a slidable stabilizing connection between said feedbar and said sewing machine frame.

3. A work feeding mechanism for a sewing machine having a frame formedwith a free ended work supporting bed, comprising a feed bar extendinglengthwise within the confines of said work supporting bed, complementalbearing means on said feed bar and on said frame including a cylindricalguide member carried by one of said parts and bifurcated jaws carried bythe other of said parts in slidable engagement with said guide member,means for shifting said feed bar in a direction lengthwise of said guidemember, said means including an oscillatory member extending lengthwisewithin the confines of said work supporting bed, means actuated by saidsewing machine for oscillating said member, a plurality of operativeconnections between said oscillatory member and said feed bar, saidconnections arranged at points on said feed bar spaced lengthwise ofsaid work supporting bed, and mechanism carried in said frame and drivenby said sewing machine for vibrating said feed bar in a directiontransversely of said guide member.

4. A four motion work feeding mechanism for a sewing machine having aframe formed with a free ended work supporting arm, comprising anelongate feed bar extending within substantially the entire length ofsaid work supporting arm, a feed dog secured to said feed bar at thefree extremity of said work supporting arm, first feed actuatingmechanism driven by said sewing machine and extending within said worksupporting arm for imparting motion in one direction to said feed bar, aplurality of operative connections between said mechanism and said feedbar, said connections spaced lengthwise along said work supporting arm,second feed actuating mechanism driven by said sewing machine forimparting motion to said feed bar in a direction substantiallyperpendicular to that imparted by said first feed actuating mechanism,an operative connection between said second feed actuating mechanism andsaid feed bar arranged at one side of said plurality of connections ofsaid feed bar with said first feed actuating mechanism, and a slidablestabilizing connection between said feed bar and said sewing machineframe at the opposite side of said plurality of connections.

5. A four motion work feeding mechanism for a sewing machine having aframe including a machine supporting base and a free ended worksupporting bed extending from said base, said work feeding mechanismcomprising a feed bar disposed in said machine supporting base andextending lengthwise into said work supporting bed, a feed dog securedto said feed bar within said work supporting bed, a slidable stabilizingconnection between said sewing machine and a point on said feed barwithin said machine supporting base, first feed actuating mechanismcarried by said frame and driven by said sewing machine, a plurality ofspaced operative connections of said first feed actuating mechanism withsaid feed bar Within said free ended work supporting bed for impartingsubstantially translatory vibration to said feed bar, second feedactuating mechanism carried by said frame and driven by said sewingmachine, and operative connections between said second feed actuatingmechanism and said feed bar to impart vibratory motion to said feed barin a direction substantially perpendicular to the motion of said feedbar in response to said first feed actuating means.

6. A four motion work feeding mechanism for a sewing machine having aframe including a frame base and a narrow free ended work supporting bedextending from said frame base and a driving shaft journaled in saidframe, comprising a T shaped feed bar, a stem portion of said feed barextending lengthwise Within the work supporting bed, a cross bar portionof said feed bar extending transversely within said frame base, feedlift actuating mechanism including a feed lift rock shaft actuated fromsaid driving shaft and extending lengthwise within said work supportingbed, feed advance actuating mechanism including a feed advance rockshaft actuated from said driving shaft and disposed within said framebase, an operative connection between said feed advance rock shaft andone extremity of said cross bar portion of the feed bar, the oppositeextremity of said cross bar portion being bifurcated, and a cylindricalguide member carried by said frame base and disposed between thebifurcation of said cross bar portion of the feed bar.

7. A four motion Work feeding mechanism for a sewing machine having aframe base and a narrow free ended work supporting bed extending fromsaid frame base comprising, a T shaped feed bar, a stem portion of saidfeed bar extending lengthwise within the work supporting bed, a crossbar portion of said feed bar extending transversely within said framebase, a guide roller journaled on a substantially vertical axis beneathsaid frame base, one extremity of the cross bar portion of said feed barbeing bifurcated and arranged to embrace said guide roller, a feedadvance rock shaft carried in said frame base and actuated by saidsewing machine, means operatively connecting said feed advance rockshaft to the opposite extremity of the cross bar portion of said Tshaped feed bar to impart vibratory motion to said feed barperpendicular to the axis of said guide roller, a feed lift rock shaftactuated by said sewing machine and extending "lengthwise within theivorkisup'porting bed, -a plurality of operative connections betweensaid feed lift ;ing machine having a frame formed with a free ended worksupporting bed comprising a feed bar extending lengthwise Within theconfines of said work supporting bed, means for advancing and returningsaid feed bar transversely across said work'supporting bed, andmeans forlifting and lowering said feed bar vertically in said work supportingbed, said last 'named'means including aroc'k shaft extending lengthwisewithin'the confines of said work supporting-bed, means actuated by saidsewing machine for oscillating said rock .shaft, a pair of rock armsextending from said rock shaft in spaced relation thereon lengthwise ofsaid work supporting bed, 'a pair of links-pivotally secured one to theextremity ofeach of said rock arms, a pair -'of feed bar arms extendingfrom said feed bar in spacedrelation thereon le'ngthwise of fSZiid WOIksupporting bed, and means pivotally securing each of said pair of linksto a respective one 'of said feed bar arms substantially verticallybeneath the pivotal connection of the link with said crock arm.

9. A founmotion work feeding mechanism-for a sewing'machine having aframe base and a narrow free ended work supporting bed extending fromsaidframe'base,

comprising a T shaped feed bar, a stem portion of'said' ifeedb'arextending lengthwisewithin the work supporting "bed, a cross bar portionof said'feed bar extending'tra'nsversely withinsaid frarne'base, feedlift actuating mechanism including a feed lift rock shaft actuated bysaid sewing machine and extending lengthwise within said work supportingbed substantia ly vertically beneath'said feed her stem portion, a pairof upwardly and outwardly extending rock'arms extending from-said feedlift rock shaft in spaced relation thereon lengthwise'offsaid worksupporting bed, a pair of feed bar arms extending from connected betweeneach of said vertically aligned feed rlift rock arms and feed bar arms,feed advance actuating ,mechanism including a feed advance rock'shaftactuated by said sewing machine and disposed within said frame base, anoperative connection between said feed advance irock shaft and oneextremity of said cross bar portion ofthe feed bar, and a slidablestabilizing connection between the opposite extremity of said crossbarportion and said frame base.

10. In a' sewing machine-having a frameincludin'g a supporting basedefining a plane of support for the sewing machine, a free ended worksupporting arm extending from the supporting base above said plane ofsupport a 'nd adapted to accommodate tubular articles lengthwise there-'on,and a bracket arm extending over said work supporting arm, stitchforminginstrumentalities including a needle carried in said bracket armfor e'ndwise reciprocating movement in a path intersecting said worksupporting arm at a stitching point thereon, a loop taker supported :forcircular movement within the confines of said work supporting arm abouta substantially vertical axis disposed in'frontof the stitching point, afeed bar extending lengthwise within the confines of said worksupporting arm and having a portion extending behindsaid stitch- ;ingpoint, mechanisrnvcarried within said frame and operatively connected tosaid feed bar for imparting move ment to said feed bar transversely ofthe longitudinal axis of said Work supporting arm, 'a'feed dogextending'trans- ,versely of the longitudinal axis of said worksupporting arm beneath s aid stitching point and being attached to saidportion of said feed bar behind said stitching point.

'11. A fo ur motion 'work feeding mechanism for a sewing machine havinga frame including a supporting base defining a plane of support for thesewing machine, and a free ended work supporting bed extending from thesupporting base above said plane of support, means defininga'substantiallyplanar work supporting area about a stitching point onsaid work supporting bed, said work feeding mechanism comprising,affeed' bar extending within said work'supp'orting bed, a feeddogsecur'ed to. s aid feed bar within said work snppo'r'tingfbed, aguide'roller journaled in said sewing machine frame on an axissubstantially perpendicular to the plane ofjsaid. work supporting areaabout said stitching point, said feed bar being provided Twithbifurcated jaws embracing said guide roller, a feed lift rock shaftcarried by said frame and actuated by said sewing machine, a pluralityof-spaced operativew connections of said feed lift rock. shaft with saidfeed bar for imrpar'ting substantially translatory vibration to saidfeed bar in a directionaxially of said guide roller, a feed advance rockshaft carried by said frame and actuated by said sewing machine, andmeans operatively connecting said feed advance rock shaft to'said feedbar to impart vibratory motion to said feed'bar perpendicular to theaxis of said guide roller.

References Cited in thefile of this patent UNITED STATES PATENTS 402,259Leilich n Apr. 30, 1898 2,386,660 Clayton Oct. 9, 1945 2,453,072 JohnsonNov. 2, 1948 2,808,793 Ayres c Oct. 8,1957

